Mechanism for converting rotary



June 5, 1951 2 Sheets-Sheet l w om HIIHI HHHH Hi June 5, 1951 QSCHWALDRe. 23,373

MECHANISM F014 CONVERTING ROTARY MOTION TO RECIPROCATORY MOTION OriginalFiled April 1, 1947 2 Sheets-Sheet 2 Reissued June 5, 1951 UNITED STATESPATENT OFFICE MECHANISM FOR CONVERTING ROTARY MOTION TO RECIPROCATORYMOTION Max Oschwald, Zuchwil, Switzerland, assignor to Scintilla A-G.,Solothurn, Switzerland, a corporation of Switzerland Section 1, PublicLaw 690, August 8, 1946 Patent expires November 24, 1964 Matter enclosedin heavy brackets appears in the original patent but forms no part ofthis reissue specification; matter printed in italics indicates theadditions made by reissue.

4 Claims.

This invention relates to motor-driven tools designated to be moved byhand, and more especially to motor-driven reciprocating hand tools suchas saws, cutters, files and the like, wherein the handle of the tool isformed by the motor housing.

It is an object of the invention to provide a light and handy toolpermitting to operate on work pieces that are too bulky to be worked ona machine tool, such as large plywood panels or lumber boards, or whichenables work to be performed in positions which are inaccessible forordinary hand tools.

A further object of the invention is to provide a mechanism forconverting the rotary motion of a motor into rectilinear reciprocatorymotion, while eliminating the vibrations generated by its masses whilethey reciprocate at frequencies of at least 3000 power cycles perminute. I

In order that the invention may be more readily understood, I will nowdescribe two embodiments thereof which are illustrated diagrammaticallyby way of example in the accompanying drawings, in which:

Fig. 1 is a perspective view of the tool as a whole; while Fig. 2 is anaxial sectional view, drawn to a larger scale, of a first embodiment ofthe invention.

Fig. 3 being a front view wherein the cover L with the reciprocatingtool is removed to showthe disposition of parts of the mechanism andsome of the counterbalance elements.

Fig. 4 is a part sectional view of a second embodiment.

Referring first to Figs. 1 to 3, the mechanism here illustrated shows amotor shaft fitted with a pinion which drives two gear wheels of equalsize positioned in substantially the same plane and on a common diameterline. One gear wheel actuates a reciprocating device, which in turnreciprocates a tool, while the other gear wheel actuates a reciprocatingdevice, which in turn reciprocates a counterbalance, the respectivemotions of both being such that the reciprocation of one of said devicesis opposed to that of the other, thereby producing a uniform andvibrationless action of the tool.

The handle of the tool is formed by the housing I of an electric motorhaving a front bearing plate 2 through which projects the motor shaft 3,which is fitted with a pinion 4. On the front bearing plate 2 two gearwheels 5 and 6 are rotatably mounted on their fixed journals 5a and 6arespectively. Both of these gear wheels have an equal number of teeth.They are permanently in mesh with the pinion 4 on the motor shaft andare driven by it when the motor is operated. On one of the gear wheels 5a crank pin 1 is eccentrically mounted. This crank pin I engages a slot8 in a carrier 9, which is fixed to a reciprocatable tool arm H) towhich the tool II is secured.

The reciprocatable tool arm Ill is mounted in a guide 14 which issupported in the casing l3 of the gear-box l2 and has at one end a headl5 adapted to grip the tool H which is secured therein by a fasteninscrew It. The tool II, in the present case a saw, is supported by meansof an adjustable guide I! with a counter-pressure roller [8 bearingagainst the tool. It is obvious that the saw may be replaced by a cutteror by a file without departing from the scope of the invention. I

On one side of the gear-box l2 a supporting plate orpedestal base I9 isarranged parallel to the motor axis. This plate is slotted lengthwiseand through the slot the reciprocating tool projects at right angles tothe base H! which permits of the latter resting on the work and beingused as in Fig. 1. On the opposite side of the gear-box a base member 28may be provided by which may support the mechanism, as for example, in avise 29. When so mounted, the reciprocating tool is directed verticallyupwards and the pedestal base l9 serves as a work stage. The pedestalbase may be adjustably mounted on the gear-box t2 and may be movable bymeans of joints (not shown), thus permitting the work to be presented tothe tool at any angle.

Diametrically opposed to the aforementioned gear wheel 5 is the secondgear wheel 6 mounted on its journal 6a. The latter gear wheel 6 isfitted with a crank pin 29 which engages with a transverse slot 2i inthe counter-balance weight 22. This weight has on its other side, atright angles to the transverse slot, two guide slots 23 fitting guides24 which are mounted-or formed in the interior of the gear-box I2 so asto keep the balance weight in rectilinear direction. 7

When, by means of the motor, the pinion 4 on its shaft and the gearwheels 5 and 6 engaging this latter are set in motion, thereciprocatable arm ID and balance weight 22 are reciprocatedsimultaneously and continuously in opposite directions. The load on thereciprocatable tool arm l and the tool II is thus counterbalanced andvibrations set up in the mechanism, even at high speeds, are avoided.Work of every description, of which the invention is capable, can beperformed safely and accurately.

In place of the crank and slot mechanism described above, reciprocationof the tool arm I0 and of the balance weight 22 may be accomplished byrods connected to crank pins on the gear wheels and 6 by spigots fixedto the reciprocating parts and riding in eccentric grooves out into theface of the gear wheels.

For greasing the moving parts in the gear-box l2, an aperture 25 isprovided therein with a copper plate 21 rockably fastened tothe gear boxby a screw 26.

The embodiment shown in Fig. 4 provides for the motor being able toserve other purposes besides the one described, for instance, to drive asmall compressor (not shown) or some other suitable implement secured toits front end. In order to facilitate conversion, an intermediatebearing plate 3| supporting the gearing components, and a disengagingclutch 30 on the motor shaft between the intermediate plate 3| and thefront bearing plate 2, may be incorporated in the mechanism. The saidintermediate bearing plate 3| may be fastened to the motor housing bymeans of screws or in some other manner.

I wish it to be understood that I do not desire to be limited to thedetails of construction shown and described, for obvious modificationswill occur to a person skilled in the art.

I claim:

' l. A mechanism for converting high speed rotar motion of a prime moverinto high speed reciprocating motion of a driven member and acounter-balancin mass comprising, a first power transmitting membermounted for rotation about an axis parallel to said prime mover fordriving said driven member, a second power transmitting member mountedfor rotation about a second axis parallel to said prime mover fordriving said mass, said power transmitting members being positioned insubstantially the same plane and spaced from one another, meanspositioned between said power transmitting members for driving saidpower transmitting members from said prime mover, guiding means for saiddriven member positioned in proximity to said second power transmittingmember and spaced therefrom, said driven member being slidably supportedby said guiding means for reciprocatin movement in a plane substantiallyparallel to the plane of said power transmitting members and extendingfrom a point in the proximity of and opposite to said second powertransmitting member to a point in proximity to said first powertransmitting member, means supporting said mass for reciprocatingmovement intermediate said driven member and said second powertransmitting means, means on each of said driven member and saidcounterbalancing mass extending transversely of said .axes and of thedirection of movement of said mass and said driven member, and a crankmember on each of said power transmitting members operatively engagingsaid transversely extending means so as to move each of saidcounter-balancing mass and driven member simultaneously.

2. A mechanism for converting high speed rotary motion of a prime moverinto high speed reciprocating motion of a driven member and acounter-balancing mass comprising, a first power transmitting membermounted for rotation about an axis parallel to said prime mover fordriving said driven member, a second power transmitting member mountedfor rotation about a second axis parallel to said prime mover fordriving said mass, said power transmitting members bein positioned insubstantially the same plane and spaced from one another, meanspositioned between said power transmitting members for driving saidpower transmitting members from said prime mover, guiding means for saiddriven member, said guiding means including a sleeve opposite to andspaced from said second power transmitting member, .said driven memberbeing slidably supported in said sleeve for reciprocating movement in :aplane substantially parallel to the plane of said power transmittingmembers and extendin from within said sleeve to a point in proximity tosaid first power transmitting member, means supporting said mass forreciprocating movement intermediate said driven member and said secondpower transmitting means, means on each of said driven member and saidcounterbalancing mass extending transversely of said axes and of thedirection of movement of said mass and said driven member, and a crankmember on each of said power transmitting members operatively engagingsaid transversely extending means so as to move each of saidcounter-balancing mass and driven member simultaneously.

3. A mechanism for converting high speed rotary motion of a prime moverinto high speed reciprocating motion of a driven member and acounter-balancing mass comprising, two power transmitting membersmounted for rotation about two acres parallel to said prime mover fordriving said driven member and said mass, said power transmittingmembers being positioned in substantially the same plane and spaced fromone another, means positioned between said power transmitting membersfor driving said power transmitting members from said rime mover,guiding means for said driven member positioned in proximity to theplane of said power transmitting members and spaced therefrom, saiddriven member being slideab'ly supported by said guiding means forreciprocating movement in a plane substantially parallel to the plane ofsaid power transmitting members, means supporting said mass forreciprocatory movement intermediate said driven member and the plane ofsaid power transmitting members, means on each of said driven member andsaid counter-balancing mass extending transversely of said asses and ofthe direction of movement of said mass and said driven member, and acrank member on each of said power transmitting members operativelyengaging said transversely ea'tending means so as to move each of saidcounter-balancing mass and driven member simultaneously.

4. A mechanism for converting high speed 1'0- tary motion of a primemover into high speed reciprocating motion of a driven member and acounter-balancing mass comprising, two power transmitting membersmounted for rotation about two axes parallel to said prime mover fordriving said driven member and said mass, said power transmittingmembers being positioned in substantially the same plane and spaced fromone another, means positioned between said power transmitting membersfor driving said power transmitting members from said prime mover,guiding means for said driven member, said guiding means including asleeve opposite to and spaced from the plane of said power transmittingmembers, said driven member being slideably supported in said sleeve forreciprocating movement in a plane substantially parallel to the plane ofsaid power transmitting members, means supporting said mass forreciprocatory movement in REFERENCES CITED The following references areof record in the file of this patent or the original patent:

UNITED STATES PATENTS Number Name Date Irick Feb. 12, 1878 Meyer June10, 1902 Ludewick Feb. 13, 1906 King Jan. 15, 1907 Specht et a1. Feb. 2,1915 Coates June 28, 1921 Hastings June 16, 1925 Maloney Mar. 8, 1927Meyer Sept. 27, 1927 Selby et a1 Nov. 8, 1927 Farrell Mar. 6, 1928Thompson Jan. 22, 1929 Thompson Jan. 22, 1929 Broillet Jan. 20, 1931Boos July 26, 1932 Johnston Dec. 6, 1938 Toop May 5, 1942 Kern May 12,1942 Burleigh Sept. 7, 1943 Curtis Mar. 28, 1944 Albertson Oct. 14, 1947

